Staining method with chromic acid precursors

Abstract

A method of staining a biological specimen in an automated staining protocol includes contacting the biological specimen with two or more precursors of a staining reagent. When combined, the precursors form the staining reagent or have the same effects on the biological specimen as the staining reagent. Preferably, the precursors are more compatible with the liquid dispensers employed in their delivery than is the staining reagent. In one example, a GMS protocol employs, instead of chromic acid, a combination of perchloric acid and sodium chromate.

What is claimed is:  
     
       1. A method of staining a biological specimen with a histological stain, wherein the specimen is treated by a process that includes treatment with a corrosive reagent, the process comprising the steps of: 
       (a) dispensing onto a biological specimen an oxidizer that is a precursor of the corrosive reagent; and  
       (b) dispensing onto the biological specimen an acid source of hydrogen ions that is other than the corrosive reagent, wherein the acid source of hydrogen ions is selected from the group consisting of perchloric acid, perbromic acid and nitric acid,  
       whereby the oxidizer combines with hydrogen ions and the combination of oxidizer and hydrogen ions contacts the biological specimen, thereby treating the biological specimen with the corrosive reagent. 
     
     
       2. The method of  claim 1  wherein the acid source of hydrogen ions is perchloric acid. 
     
     
       3. A method for detecting the presence or absence of microorganisms in a biological specimen in an automated histological staining process, comprising the steps of: 
       (a) treating the biological specimen with a staining reagent wherein the treatment comprises dispensing from separate liquid dispensers, onto the biological specimen, a source of chromate ions and an acid source of hydrogen ions, the source of chromate ions and the acid source of hydrogen ions being other than chromic acid, wherein the acid source of hydrogen ions is selected from the group consisting of perchloric acid, perbromic acid and nitric acid, thereby combining chromate ions and hydrogen ions, wherein the combination of chromate ions and hydrogen ions contacts the biological specimen;  
       (b) washing the combination of chromate ions and hydrogen ions from the specimen;  
       (c) staining the washer specimen with a histological stain suitable for the detection of microorganisms; and,  
       (d) detecting the presence or absence of microorganisms in the specimen.  
     
     
       4. The method of  claim 3  wherein the acid source of hydrogen ions is perchloric acid.